# Triangles | NCERT Class 10 Maths

In the introduction section of this chapter, it is mentioned that the aim is to study triangles that have the same shape but not the same size. Such triangles are known as similar triangles. Further, it is proposed that two polygons of the same number of sides are similar, if (i) their corresponding angles are equal and (ii) their corresponding sides are in the same ratio (or proportion). For the second exercise, the similarity of triangles is taken up and it is noted that two triangles are similar when - corresponding angles are equal and their corresponding sides are in the same ratio (or proportion). In the third part of the chapter, the criterion for similarity of triangles is presented (AAA, AA, SSS and SAS). Finally, the chapter covers concepts like the areas of similar triangles and the Pythagoras theorem.